how many fishes in a tank

Question
I'm having a few questions about pet fishes.i'm having a freshwater aquarium with some golds,sharks,silver sharks.so far things are good.

1.At which condition we can say there are too much fishes in a tank?
2.what are the effects of having too much fishes in a tank?how its related to their growth?

Answer
Hi Mick,
  That isn't a simple question.  As a VERY rough rule, people say something like 1 inch of fish per gallon of water.  So you could have 10 1-inch fish in a 10 gallon tank.  That said, you could not have 1 10-inch fish in the same tank.  How many fish depends on many things like the activity of the fish, how well they get along, how much structure (plants, wood, rock) you have in the tank, how much filtration you have and how frequently you do water changes.

  You should be changing 25% of the water once a week, every week to keep your fish happy and healthy.  If you do not do enough water changes, then nitrogen products build up in the tank, and that stunts growth, or worse.  

-- Ron C.
  rcoleman@cichlidresearch.com
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